I have buffs and would highly recommend them as a good backyard, utility type goose. They're very hardy, vigorous, excellent foragers, have docile temperaments, great feed to meat conversion, easily handled. The only thing I would say that is widely circulated about the American but not necessarily true is that they are quiet. They may be quiet
er than some other breeds, but mine are not what could at all be interpreted as quiet. They get to chattering several times a day and night and can be quite loud about it. I don't think you'll find any goose that is absolutely, positively quiet though so I don't count that against them. I also have a medium to large flock depending on the time of year -- we're down to 10 right now after the Christmas season, but won't go any lower than that so the noise level here
is cumulative, which I'm sure makes a difference. When 10 of them get to honking all at once, they're like My Big Fat Greek Wedding, everyone has to get their say in and they try to "yell" it over the others.
Productivity and size-wise the toulouse is going to be quite similar to the American Buffs, the Buffs are thought to be slightly more prolific layers but some also say they tend towards being slightly less fertile so it equals out in the end. The toulouse are known to be slightly less docile than the Americans but among individuals the difference can be negligible at best. Between those breeds I would say your choice will ultimately come down to looks. If you prefer one to the other I would not let any of the breed traits scare you off. The two are close enough in comparison that any difference shouldn't be all that great.
This is a gaggle of Americans of Mixed Ages to give you an idea. The ones who look like they do not belong are American Blues and the one out front is an American Lavender. As you can see in the background they happily coexist with turkeys and chickens -- and though you cannot see any ducks in the background they too are part of our mixed flock.